Sorry to disappoint, it’s just a simple concept I’ve not been able to impart to my players well.
In any Fantasy setting there are Gods/Powers. Full stop.
Saying that you are an atheist or even agnostic, is like saying there is no wind, or nothing lives under the waves.
Or in the case of an agnostic, I don’t know what might be down there, or if anything is down there.
As to who the deities are….
They are at once a Meme not the internet thing, but the cultural thing. And a power with agency, goals, and a force of will. What they don’t have is hopes and dreams (usually).
We are talking theology, so logic is malleable.
Let’s make up a god or two…
Kesandra the goddess of motherhood.
For most, she represents birthing, sacrifice, maturity, hard lesson learned, soft encouraging scolding, maternal femininity.
In some areas, conservative/rural she also represents fertility and good crops/weather for the crops.
For very few (a town or an order), she represents the protection of the home, the protection of loved ones.
Brutica the god of righteous anger.
For most he represents punishment for wrongdoing. In some places that is the city guard, or the secret police. For others it’s an unusually effective fighting force. However for the “Initiated” he represents the force that gives people the fortitude to right wrongs.
In a few towns that suffered siege, and where able to repel land even defeat the assault without external help, become a Patron of the city.
Cities may have more than one Patroness, but usually one founding Patroness and several promoted patrons…some of the following having gained primacy in a city or region.
With those two gods you might start, or simply have a Pantheon. A complete religious philosophy. But the older an area is, the larger the Pantheon, until a singular faith comes into being. But I think that argument is best left off gaming at all costs (yes I know many gamers like making Monotheism the enemy of the world…but it’s a tiresome trope, and directed at the “Satanic Panic” that was stupid in the first place, no reason to add fuel to the fire.
Anyway, back to topic at hand. You have Kasandra and Brutica. And you might have the idea that this provides a complete philosophy or at least a synergistic philosophy, but it doesn’t. It doesn’t. However, these two entities with their limitations are the foundations of a societies social norms.
Strong family bonds, respect for rearing of children with strong lessons. But also the quest for righting any perceived wrong.
This would lead to family feuds. And as long as no new entities enter the picture, institutions need to be created to not allow the destruction of this society or new Powers need to come in.
Examples of institutions.
A judicial system, a priesthood to balance things, alternative philosophy.
But what of the two deities themselves???
They change with the times. But not on a scale that Player Characters might notice, but on a scale players might.
More sophisticated, more belligerent, more war like…
In most cases, (99.999%) of the cases, the locals follow the two gods, some with a preference, some with a hard preference. But on occasion a new or older version of one of the deities and their philosophy apear.
Perhaps Kisandra/Kesandra in a self sufficient town in a small Vale between mountain ranges became the All Mother. Not the incarnation of motherhood, but also of guardianship of the soul.
Her followers would view things differently, the goddess herself is both things, but for those who follow a more overall image of her, she would be very different.
As to the entity she thinks she is the same, but one group, expects a more martial/militant side of her disgust of the undead.
The people reflect this, they view any necromancy including calling on dead ancestors as blasphemy. But most might view comunication with ancestors as a gift of Kesandra.
The goddess herself does not see the difference. For one granting views into the ancestors thoughts, of good motherly love….at the same time, any necromancy of calling on the dead, as the worst of the worst and is no longer in her favor or protection.
As to beneficent gods being stretched thin, trying to do the most good for the most people is an equation that is hard to compute, so they are stretched to the max. However, a dream, a thought, an obsession in the mind of those already primed to follow is easy to manifest. An angelic being destroying the enemies of her followers is hard.
Inversely, a god/power who is only about their own aggrandizement/burning the world…they can be more focused. And those with wider influence but less zealotry try to be more subtle, cause they can be and they have a much wider net to do crowdsourcing.
Can a deities followers war with each other??? Sure!!! And different aspects may favor different sides throughout the conflict.
They may even favor one person above all others, but side with the opposite side in the conflict.
Gods and Powers are alien. It’s not just the long game, but their game is different. Who their followers are is not equal to those they influence. And who they influence is not limited to who follows them.
But their power might be influence by how absolutely some of their believers believe.
From a GM perspective, I want my PCs to have entities they follow, or at least favor. But I want them to follow many deities.
Perhaps the clerical orders are a societal norm.
The tiller god (god of food growth)
The fertility god ( god of procreation)
God of motherhood ( god of protection)
God of law ( god of keeping order and avoiding unnecessary violence)
God of death ( god of Shepard’s and of keeping souls from straying and keeping the dead from raising)
God of war ( god of renewing and spreading wealth)
God of voyages ( god that keeps travelers and innocent safe as well as the god of revelation who give insight to new things)
But the clerical orders might not follow what their deity is.
It is very easy for the clerics of the “God of Voyages” clergy to be inn keepers or Dock Workers…yet adventures to be the focus of the deity.